a, 149 - (35:x+3).17 = 13
<=> (35:x+3).17 = 136
<=> 35:x+3 = 8
<=> 35:x = 5
<=> x = 7
b, 1 x 32 + 7 x 8 + 4 x = 200 x
<=> (1000+100x+32)+(700+10x+8)+(40+x) = 2000 + x
<=> (1000+32+700+8+40)+(100x+10x+x) = 2000+x
<=> 1780+111x = 2000+x
<=> 110x = 220
<=> x = 2